Xanthomonas gum is produced in a broth by fermentation. Upon completion of the fermentation the gum can be recovered from the broth by using one of several precipitating agents. One precipitating agent is an alcohol usually isopropyl alcohol. Another precipitating agent is a quaternary compound. Still another precipitating agent is the calcium ion combined with an alkaline pH. When the precipitation is conducted with the calcuim ion the type of calcium-xanthomonas gum complex which is useful in the practice of this invention is formed. Heretofore the calcium-xanthomonas gum complex was subsequently oven dried at a temperature of about 100.degree. C. to 145.degree. C. over a period of about 20 to 30 minutes. It is also known that xanthomonas gum precipitated by other means can be hydrated and susequently precipitated with the calcium ion at an alkaline pH to produce the type of calcium-xanthomonas gum complex useful in the practice of this invention.
Aqueous sols of calcium-xanthomonas gum complexes are plastic in nature and exhibit relatively high viscosities and gel strengths when compared with sols of other gums. These features have made xanthomonas gum an important commercial gum. The oven dried calcium-xanthomonas complex, however, is slowly rehydratable in water and does not rehydrate in brines. Its lack of rehydratability in brine has been a limitation to its usefulness in oil well drilling where thickeners and suspending agents are used to suspend cuttings and in fracturing earth strata where thickeners and suspending agents are used to suspend proppants.